Arctic Sea Ice Reaches Third Lowest Point

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Sea-ice coverage in the Arctic experienced a highly unusual
late-season decline, falling to its third lowest amount on
record, the National Snow and Ice Data Center (NSIDC) announced
today (Oct. 4).

It added that the abnormal event emphasizes the Arctic's growing
vulnerability to summer melt.

Arctic sea ice goes through a normal cycle of summer melting and
refreezing during the winter months, but the overall ice coverage
has become younger and thinner during its dramatic decline over
the past 30 years. Researchers who had assumed the
end of the melt season had arrived when the ice coverage
began growing after Sept. 10 were surprised to see it shrinking
once again sometime after that and up until Sept. 19.

"The late-season turnaround indicates that the ice cover is thin
and loosely packed – which makes the ice more vulnerable both to
winds and to melting," said Walt Meier, NSIDC research scientist
at the University of Colorado in Boulder.

Arctic sea ice reached its lowest point of 1.78 million
square miles (4.60 million square kilometers) on Sept. 19, which
gives 2010 the record for the third lowest ice coverage ever in
both daily and monthly average tallies. That puts the ice
coverage below last year's record, with the
lowest- and second-lowest coverage taking place in 2007 and
2008.

The oldest and thickest ice (five years or older) has vanished
almost entirely in the Arctic. Less than 23,000 square miles
(60,000 square kilometers) of the old ice remained in September,
as opposed to an average of 722,000 square miles (2 million
square kilometers) that lingered by summer's end in the 1980s.

There's perhaps some hope for the ice coverage, because of a
rebound in younger ice coverage (as new ice forms) over the past
two years – even as total ice coverage has continued to fall.
Whether or not the younger ice can survive the next several
summers and slow the great decline remains a mystery, researchers
say.

But either way, all signs point to the Arctic ice coverage
breaking up during the next few decades. The
fabled Northwest Passage has already opened for a few bold
ship captains.

"All indications are that sea ice will continue to decline over
the next several decades," said Mark Serreze, director of the
NSIDC. "We are still looking at a seasonally ice-free Arctic in
20 to 30 years."